Characterizing DP-steels using micromechanical modeling of cells

Dual phase (DP) steels having a microstructure consisting of martensite dispersed in a softer matrix called ferrite have received colossal attention due to their appealing combination of high strength, high work hardening rate and good ductility, which are favorable properties especially for forming processes. A model based on micromechanical modeling of cells is developed to capture the mechanical behavior of the DP-steels. The single-phase material behaviors of the constituents, which are the only material description required in micromechanical modeling, are produced in this work. Different material considerations, which are shown to have significant influence on the material behavior, are employed in the model. These include ferrite grain size, martensite softening by carbon dilution and particle size distribution effects. DP-steels of different volume fractions of martensite are produced in this work from heat treatment of a low carbon steel. Results of tensile tests are compared to the model predictions, which show good agreement between the experiment and model in terms of stress strain trends, in general, and specifically the UTS and the uniform strain and in terms of the mechanics and mechanisms of deformation, which takes place in DP-steels.